On Wednesday, 11 December 2013 13:37:24 UTC, Philipp Meier wrote: > > Hi, > > Am Mittwoch, 11. Dezember 2013 14:27:01 UTC+1 schrieb Mikera: >> >> You can't really avoid the instance checks: the underlying mechanic is >> that the JVM needs to figure out somehow at runtime which overloaded method >> version to call, since all it knows at compile time is that it has an >> arbitrary Object. >> >> instance? is the simplest way to do this. There are some fancier ways >> (e.g. using reflection or invokedynamic) but your case doesn't have very >> complex dispatch requirements so instance? checks are almost certainly the >> best option. >> >> The good news is that instance? checks are extremely fast on the JVM so >> performance will still be great (certainly far better than if you used any >> kind of reflection....) >> > > Implementing a clojure protocol will give you fast dispatch on the first > argument's type. >
Very true... it's a tradeoff: - protocols allow open extension (which doesn't appear to be needed here?) - instance? checks are even faster (although protocol dispatch is still pretty fast) - protocols have some other quirks (e.g. not allowing primitive arguments) In the case we have here (a small fixed number of types, no open dispatch required) I think I would prefer instance? checks (especially given a nice macro to remove the boilerplate). -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
